An indication of the dreams having greater meaning within Troilus and Criseyde:

1. Book II : line 90ff

“this nyght thrie,/To good mot it turn, of you I mette”
good fortune has come on it, the dream has added the plot

Criseyde claims to have dreamt of her uncle 3 times the night before
making her dream connected to the plot whether it predicted his arrival
or induced it.

We can agree, as people (except Pandarus) always have, that dreams are
significant and therefore look for the meanings of the dreams and
how they aid or correlate to the plot and assist his purpose announced
in the Proem of Book I.

2. Criseyde’s Eagle Dream:
Book II: lines 925ff

This dream is the climax of Book II because nowhere else is the
violence greater. It is important to note that this book is not in the
Filostrato so Chaucer has chosen to include it to assist his own
purpose; to demonstrate the double sorrow of the lovers.

The Eagle swapping her heart for his own is highly symbolic, hence she
no longer has her own heart.

In the dream is the Eagle’s prey just as she is Troilus’s prey.
I believe that he is the Eagle and that she is being forced to give up
her heart for him and in turn receive his. This also can be
considered to be what is actually happening in the plot as Pandarus is
in fact asking her to give up her heart for Troilus, to stop his
sorrow. She becomes a defenceless prey being held responsible for
whether Troilus should live or die.

She feels no fear or smart because Antigone has persuaded her that love
is painless. Also being a widow this is not her first love and
therefore her heart has been stolen before. If she did feel love for
her first husband then it is a familiar pain and she is so familiarised
with it that she no longer feels it become immune. However, if
she did not love her first husband her love is painless because she has
played the “game” of love before.

The eerie inclusion of “bone” in the imagery also adds a sinister
quality to the dream.

Earlier on in the book Criseyde associates love with the loss of freedom

3. Book II: Lines 781ff
Ther is in love, som cloude is over that sonne.
Therto us wretched wommen nothing konne.

The dream is therefore a communication of this view of entrapment.

4. Troilus’s Boar Dream:

Book V: Lines 1235ff

This dream occurs two months after Troilus has unsuccessfully waited
for Criseyde at the gate. His mind is full of doubts and these are
visualised in his unconscious.

He dreams of a Boar in the forest, kissing his lady.
The dream is obviously mirroring the newly founded relationship between
Diomede and Criseyde, to the reader. However not to Troilus, for
he does not yet know of the affair. In this way his dream is somewhat
prophetic.

Cassandra is a mythological character. She is familiar with
Statius’s Thebaid and known
to have access to the prophecies of the past the present and the future.

Unlike Boccaccio, who allows his hero to interpret his dream, Chaucer
employs Cassandra for this purpose. Troilus won't believe Cassandra as
it is her fate to have her prophecies ignored. However the
interpretation of the dream is the same in both versions.

Cassandra in her explanation shows how the symbol of the boar is linked
to Diomede through ancestry, as Diana sent it to disrupt the Greeks and
then Meleagre (Diomede’s ancestor) killed it.

The history she gives, is one that is over brimming with details of
death and the link with Thebes. (V 1464ff). Through this
association the dream confirms Troilus’s “fatal destyne” ( V 1)

The dream can be seen to drive the poem towards its ending.

In the Filostrato, Troiolo
dreamed that the boar was tearing out Criseyde’s heart with its tusks,
and that she took it as a pleasure. Instead, Chaucer transfers
this act of tearing to the eagle. I believe that this is too violent
for Chaucer’s version as although Diomede’s wooing is cunning, it does
not seem to take a great effort to persuade Criseyde. Chaucer would
need to take the violence out of the dream to make Criseyde seem less
like a victim and more like an active partaker kissing the boar.